The present invention relates generally to the manufacture of glass and, more particularly, to the high volume production of glass containers wherein both colored glass and clear glass shapes may be produced simultaneously.
Heretofore, it has been common to either dedicate an entire glass melting furnace to the production of colored glass or to treat clear glass produced by a melting furnace by adding a color concentrate upstream of the glass forming machine in a forehearth region. Such known forehearth coloring technology has several shortcomings, the more notable being the limitation on glass throughput; the high raw material cost of color concentrates; as well as the high maintenance costs and associated downtime of the mechanical color stirrers. In addition, certain color additions requiring longer dwell times or higher melting temperatures, such as that required for producing amber colored glass, for example, cannot be produced by the forehearth coloring technique.
In prior attempts to increase throughput and production flexibility of colored glass, it has been proposed to utilize a so-called "color cell". The prior color cell employed a vertical flow-through refractory structure which diverted clear glass flow from a melting furnace. Color concentrates were added along with colored cullet (recycled glass) and melted in an electrically heated zone within the color cell. Mechanical stirrers were situated in a discharge portion of this prior arrangement in order to achieve homogeneous color and temperature. Energy costs as well as raw material costs were relatively high in this prior color treatment process, while production rates were concurrently low, on the order of about three tons per day.
The present invention solves many of the problems of the prior art by providing a process and apparatus for the simultaneous production of clear and colored glass at production throughput rates of up to 250 tons of glass per day. The present invention utilizes high levels of colored cullet and coloring agents in raw material form to provide greater plant throughput, while achieving significant material cost reduction and increased cullet usage than heretofore possible.
The present invention further provides a system in which the existing glass melting furnaces in a glass plant supply molten glass to the apparatus of the invention. In this manner, the existing melting furnaces realize a longer refractory life and operate at lower fuel consumption levels by producing clear glass only.
Still further, the glass coloring system of the present invention melts the cullet outside of the existing clear glass melting furnaces to increase production capacity for the entire facility while providing rapid color changes with a minimum of downtime. Clear glass production proceeds simultaneously with or in place of colored glass production or during color changeover periods.
The present invention, in addition, provides a method and apparatus for mixing, treating and homogenizing clear molten glass with preheated or cold cullet and raw material coloring agents which produces colored glass of superior quality, high throughput rates and at a low cost relative to known coloring systems.
The present invention further relates to apparatus and methods for controlling the flow of molten glass in a channel, and more particularly, to an apparatus and a method for controlling the flow of molten glass in a treatment chamber, a channel supplying glass to an inlet of a chamber and a channel receiving glass from an outlet of the chamber.
In apparatus for producing glassware articles, glass is melted in a furnace which delivers the molten glass via a channel or forehearth to a glassware forming machine. Gobs of molten glass are removed from the channel and are formed by the glassware forming machine into glassware articles. The apparatus is arranged such that the level of molten glass in the channel and furnace determines the weight of the article. In many applications, it is somewhat critical that the weight of the glassware articles produced by the glassware forming machine does not vary from one article to another. Thus, it is important to maintain a consistent level of molten glass in the apparatus so that glassware articles having consistent weights are produced.
The present invention, in this regard, further provides an apparatus and method for controlling the volumetric flow of molten glass in a channel to a color treatment chamber so as to produce glassware articles having consistent weights.